Knurling machine



April 25, 1944.

N. A. JUNG ET AL 2,347,350 KNURLIN MACHINE Filed May 12, 1942 25 W; 25 T 25b 22a Patented Apr. 25, 1944 UNITED STATES PATENT OFFICE KNURLING MACHINE Norbert A. Jung, Si-lverton-,- Ohio, and Harry F.

Tenkotte, Covington,.Ky., assignors to Aluminum Industries, Incorporated, Cincinnati, Ohio, a corporation of Ohio Application May 12, 1942, Seliial No. 442,666

4 Claims.

This invention relates to knurling machines and more particularly to machines for performing knurling which is so heavy that it cannot be satisfactorily accomplished in knurling machines available on the market today. The machine of our invention, as will readily be under.- stood, can be used for any kind of knurling operation but we will described it in connection with a certain knurling operation in connection with which great difficulty was had.

In the manufacture of shot for a 37 millimeter cannon, an operation must be performed to produce a tooth-like arrangement in annular ridges about the projectile, which ridges are disposed in the region onto which the rotating band is pressed. We have found that with the machine of this invention, the operation can be performed very simply and expeditiously. It is, therefore, an object of our invention to provide an apparatus for performing heavy duty knurling of all kinds. It is a further object to provide such an apparatus which will be extremely simple in construction, accurate in adjustment and in which the knurling tool may be removed and replaced without changing the set up. These and other objects of our invention which will be described more in detail hereinafter or which will be apparent to one skilled in the art upon reading this specification, we accomplish by that certain construction and arrangement of parts of which we shall now describe an exemplary embodiment,

Reference is made to the drawing and in which:

Figure 1 is a front elevation with parts broken away of an apparatus according to our invention,

Figure 2 is a cross sectional view of the same taken on the line 22 of Fig. 1.

Figure 3 is a cross sectional view taken on the line 33 of Fig. 1.

Figure 4 is a fragmentary view in elevation of a shot upon which the knurling operation is to be performed.

Figure 5 is a fragmentary cross sectional view taken on the line 5-5 of Fig. 4, and

Figure 6 is a view similar to Fig, 5 showing the same after knurling,

Briefly, in the practice of our invention, we employ a conventional hydraulic press to the piston of which we attach a knurling tool which is vertically reciprocable in a jig. The object to be knurled, i. e., the shot is placed in the jig in roller bearings so that when the ram of the press descends and the knurling tool bites into the work piece it rotates the work piece in the roller bearings while performing the knurling operation-. Shields are provided to prevent steel shavings or other grit from getting into thebearings.

Referring more particularly to the drawing in Figure 4, there is. shownthebase end of a shot indicated generally at Ill and having a portion 1 I of reduced diameter on which are four annular ridges l2. These are produced bya turning operationor the like. In practice a copper sleeve is pressed over the shot in. the region of the portion II and in order that rotation of the rotating-band may be imparted to the shot'its'elf, the. ridges I! have to be toothedpor knurled so that they may bite into the material ofthe rotating band when it is pressed thereon, It is to this knurling operation that our invention isdirected, The material from which the shot ismade is very hard and the-teethto be produced in, the ridges l2 are very deep and must extend below the surface II. We have foundthat the ordinary knurling machine is under a tremendous load which must be put upon it to produce the desired results.

We will not describe the hydraulic press with which this invention is usedsince it forms no part of our invention and any suitable press may be employed. We provide a jig indicated generally at l3 having front and rear plates l4 and [5 respectively. The plate [5 is fastened to the jig in any suitable manner and carries a 10- cating stud [6 which may be fixed in position by means of a lock nut I l. The plate l5 holds in position the roller bearing indicated generally at la, the inner race of which carries a sleeve |8a which also acts as a shield and which is accurately machined to a diameter of 1 of an inch greater than the finished diameter of the base of the shot. The front plate I4 is perforated as at l5 to permit insertion of the shoe into the jig and is fastened to the jig l3 in any desired manner. The plate l4 holds in position the roller bearing indicated generally at la, the inner race of which carries the sleeve [9a which is accurately machined to a diameter of of an inch larger than the corresponding portion of the shot. In the description thus far, it will be clear that the shot may easily be inserted base first into the jig and will have a bearing at two spaced areas in accurately fitted sleeves which are mounted in roller bearings so that the shot is free to rotate freely. The axial position of the shot, of course, is determined by the position of the stud IS.

The jig I3 is vertically slotted as best seen in Figure 3, with the slot 20 intersecting the bore of the jig. The slot 20 is closed by a cover plate 2| which is fastened to the jig in any suitable manner. Within the slot the bar 22, upon which is mounted the knurling tool 23, is reciprocably mounted. From Figure 3 it will be apparent that the bar 22 is provided with a shoulder 22a which bears against a shoulder 20a with the slot 20 so that the bar 22 is confined except for vertical reciprocable movement by the sides of the slot 20, the shoulder 211a, and the cover plate 2|. The knurling tool 23 may be adjusted with respect to the bar 22 by shimming between the two. This is done, of course, to compensate for wear or if a deeper cut is. desired. The knurling tool 23 resembles a rack having teeth corresponding to the teeth to be produced in the ridges l2. When power is ap--- plied to the ram of the hydraulic press and thereby to the bar 22 causing the knurling tool to descend and engage the shot,. the shot is rotated as the knurling tool descends to the dotted line position of Figure l which is the bottom line of the stroke and in which the knurling tool barely clears the shot, thereby producing the indentations l2a shown most clearly in Figure 6.

The bar 22 is provided at its upper end with a slot 22a which is engaged by a hook-like element 25a of the adaptor 25. The adaptor 25 may be fastened in any desired manner to the ram of the hydraulic press, as for example, by being screwed thereto and held in position by a pin. The bar 22 is held against lateral movement by the screw 25b.

' From the foregoing if it be desired to replace the knurling tool, it is only'necessary to remove the plate 2|, loosen the screw 25b and withdraw the bar 22 with theknurling tool 23 to the right as seen in Figure I. Then any desired adjustment may be made of the knurling tool with respect to the bar or the tool may be replaced by a different tool. All this may be done without changing the set up of the apparatus in any way.

While we have shown our invention as applied to a knurling machine fora particular knurling operation, it will be clear that it is capable of widely various uses and we, therefore, do not intend to limit ourselves except as pointed out in the claims which follow.

Having now fully described our invention what we claim as new and desire to secure by Letters Patent, is:

1. A knurling tool for use with a hydraulic press comprising a jig, means for supporting a work piece in said jig in freely rotatable condition, a vertical slot in said jig, a cover plate cooperating with said slot to form a guide, a bar reciprocable in said guide, said bar carrying a knurling tool in a position to engage said work piece upon reciprocating movement of said bar and means for attaching said bar to the ram of pj said press.

2. An apparatus according to claim 1 in which themeans for attaching said bar to the ram of said press comprises a hook-like element on the end'of said bar and a slot on said ram having a shoulder arranged to engage the hook-like portion on said bar whereby said bar may be slid out of engagement with said ram and a set screw for holding said bar against lateral movement.

3. A knurling tool for use with a hydraulic press orthe like, comprising a jig, means for holding a work piece in freely rotatable condition in said jig comprising spaced bands of roller bearings having internal surfaces machined to fit closely corresponding parts of the Work piece and a tool operable on the work piece between the bands.

4. A knurling tool for use with a hydraulic press or the like, comprising a jig, means for holding a work piece in freely rotatable condition in said jig. comprising spaced bands of roller bearings having internal surfaces machined to fit closely corresponding parts of a workpiece, a tool operable on the work piece between the bands, and means for locating said work piece axially comprises a stud threaded into said jig and fixed into position by means of a lock nut.

NORBERT A. JUNG. HARRY F. TENKOTTE. 

